Because some of our suppliers charge a shipping fee if the purchase order is under a certain value to would be very handy if you could assign a minimum order value to a purchase order before it can be placed/saved or at least a warning that it is under.

For example for one of our suppliers if the order is over £250 then shipping is free, if it is under £250 then they charge shipping.

I presume the best way would be on a supplier level so you could set in your suppliers register a minimum value amount and then when creating a PO it would look up that data and then alert you if it is under the set value